1. Field of the Invention
The present invention is concerned with a filling assembly for aseptically operating deep-drawing packing machines hereinafter briefly referred to as FFS machines.
2. Description of the Prior Art
FFS machines of this type for shaping (molding of, for example, container cases from the web of packing sheet by deep-drawing), loading and sealing of a web of packing sheet moved through the machine are adequately known and used in the art. Depending on the product and the type of offer thereof in the store concerned (in chilled boxes or on non-chilled shelves) measures will have to be taken to insure that, on the one hand, the web of packing material and the covering foil be held in sterile condition and, on the other hand, remain in aseptic condition during movement thereof through the machine, i.e. FFS machines of this type, for aseptical operations, are furnished with a sterile pipe under a slight excess pressure. All these demands are met by the traditional FFS machines of this type which, in addition and in accordance with the requirements of the operators of such machines running at high speed and being expected to involve low stoppage times for inevitable washing and cleaning operations especially of the loading machines or filling stations (e.g. daily basic cleaning and intermediate washing in case of a change from the filling of one product to another). In this respect, the sterile pipe constitutes a problem as the filling station along with its at least one loading tube is to be suitably integrated thereinto, it being required that sterile conditions be maintained and the washing and cleaning demands be met.
In this respect, two basic principles have been conventionally used, i.e. a drainable tank for accommodating the back-flowing cleaning and washing fluid is arranged underneath the molded web of packing sheet in the filling region, and a horizontally displaceable tank collecting the back-flowing cleaning fluid is arranged underneath the metering arrangement, i.e. underneath the at least one loading tube, between the metering arrangement and the sheet of packing material within the sterile pipe. As the collecting tank, in the former instance, is located underneath the web of packing sheet or under the conveying region thereof, respectively, it being necessary for the tank's opening rim to be in closely abutting relationship, during cleaning, with the so-called plate of the metering arrangement, the web of the packing sheet for each cleaning operation is to be severed and removed from the region of the filling assembly inevitably resulting in correspondingly extended stoppages of the whole machine. It is true, the second principle does not require severing and removal of the web of packing sheet, however, the entire adjusting mechanism for displacing the collecting tank is to be located on the sterile pipe and, moreover, drainage of the tank through ports within the wall will have to be safeguarded. None of these two principles enable the FFS machine, during washing and cleaning of the metering arrangement and of the filling assembly respectively, to continue its operation, irrespective of whether it is an intermediate washing or a basic cleaning operation.